The present invention relates to methods for building three-dimensional (3D) objects. In particular, the present invention relates to methods for building 3D objects with layer-based additive techniques.
Rapid prototyping/rapid manufacturing (RP/RM) systems are used to build 3D objects from computer-aided design (CAD) models using one or more layer-based additive techniques. Examples of commercially available layer-based additive techniques include fused deposition modeling, ink jetting, selective laser sintering, electron-beam melting, and stereolithographic processes. For each of these techniques, the CAD model of the 3D object is initially sliced into multiple horizontal layers. For each sliced layer, a build path is then generated, which provides instructions for the particular RP/RM system to form the given layer. For deposition-based systems (e.g., fused deposition modeling and ink jetting), the build path defines the pattern for depositing roads of build material from a moveable deposition head to form the given layer. Alternatively, for energy-application systems (e.g., selective laser sintering, electron-beam melting, and stereolithographic processes), the build path defines the pattern for emitting energy from a moveable energy source (e.g., a laser) to form the given layer.
In fabricating 3D objects by depositing layers of build materials, supporting layers or structures are typically built underneath overhanging portions or in cavities of objects under construction, which are not supported by the build material itself. A support structure may be built utilizing the same deposition techniques by which the build material is deposited. The host computer generates additional geometry acting as a support structure for the overhanging or free-space segments of the 3D object being formed. The support material adheres to the build material during fabrication, and is removable from the completed 3D object when the build process is complete.
While fabricating 3D objects with layer-based additive techniques, a common issue for manufacturers is the identification and tracking of the 3D objects during post-build operations. This is particularly true for rapid manufacturing applications, where multiple RP/RM systems continuously build 3D objects based on large-volume job queues. In these cases, it may be difficult to identify and track the large quantities of 3D object built, particularly when such 3D objects typically require post-build operations before completion. Thus, there is an ongoing need for methods for identifying and tracking 3D objects during fabrication processes with layer-based additive techniques.